Estrogen replacement therapy is not conducive of venous thromboembolism

The effect of superstition on the day of discharge from maternity units in Northern Ireland: "A Saturday flit is a short sit"

The impetus for evidence-based practice arose from the science of maternity and childcare. Yet this has to coexist with patient preferences which are often based on a belief system far removed from science. This paper shows how a superstition, which suggests that moving on a Saturday is unlucky, affects a large proportion of discharges from maternity units in Northern Ireland. This is a descriptive study of the 77 018 patients admitted to maternity units in Northern Ireland between 1994/95 and 1996/97. Overall 3819 (35.7%) fewer patients than expected were discharged on Saturday and 2445 (23.2%) and 1834 (17.4%) more than expected were discharged on Friday and Sunday respectively. This means that at least 8097 patients were probably affected by the superstition. In an evidence-based world patient preferences are still evident.

Recent advances in the treatment of thromboembolic diseases: Venous thromboembolism

Venous thromboembolic diseases are the major concern of rising cost of healthcare and are commonest health problem across the globe. Both genetic and acquired risk factors are believed to be strongly linked with these diseases. Commonly encountered problems to the therapy include dose fixing and routine monitoring, yet some serious problems of bleeding also necessitate the immediate need to develop new agents. The review is primarily concerned with the new developments in the treatment of thromboembolic diseases. Therapeutic applications of anticoagulants, antiplatelets, and thrombolytics have been discussed in enough detail.

Exogenous Sex Hormones and Thrombophilia

Worldwide, hundreds of millions of women use exogenous estrogens in contraceptives or for postmenopausal hormone replacement. Exogenous estrogens increase the risk for venous and arterial thrombosis. This article reviews the use of exogenous sex hormones in women with thrombophilia.

Hormone replacement therapy and cardiovascular disease: increased risks of venous thromboembolism and stroke, and no protection from coronary heart disease

Hormone replacement therapy (HRT) was increasingly promoted over the last 40 years to improve quality of life, and to reduce the risks of osteoporotic fractures and coronary heart disease (CHD). In recent years, observational studies, randomized trials and systematic reviews of such trials have shown that HRT does not reduce, but actually increases cardiovascular risk. HRT increases the relative risks of venous thromboembolism (twofold), and of fatal or disabling stroke (by 50%); whilst increasing the early risk of myocardial infarction and having no protective effect against CHD on longer term use. Possible mechanisms for these increased cardiovascular risks include down-regulation of several inhibitory pathways of blood coagulation, resulting in increased coagulation activation, which promotes venous and arterial thrombosis. The implications for prescription are discussed, as are lessons for future evaluation of health care interventions.

Female hormones and thrombosis

Exogenous hormones are used by more than a hundred million women worldwide as oral contraceptives or for postmenopausal hormone replacement. Oral contraceptives increase the risk of venous thrombosis, of myocardial infarction, and of stroke. The risk is highest during the first year of use. The venous thrombotic risk of oral contraceptives is high among women with coagulation abnormalities and with so-called third-generation contraceptives (containing desogestrel or gestodene). The risk of myocardial infarction does not appear to depend on coagulation abnormalities or the type of oral contraceptive. Hormone replacement therapy increases the risk of venous thrombosis. This risk is also highest in the first year of use and among women with coagulation abnormalities. The risk becomes very high in women with a previous venous thrombosis. Randomized trials have not confirmed a beneficial effect of postmenopausal hormones on the occurrence of myocardial infarction.

HRT and the risk of deep vein thrombosis

Venous thromboembolism (VTE) has long been recognized as a risk of oral contraceptive use in women, but until recently hormone replacement therapy (HRT) was not thought to be associated with a similar risk; the epidemiological literature having been reassuring. The recent publication of four independent epidemiological studies has changed our perspective on VTE risk on HRT. These studies suggest that the risk of VTE may be increased by up to three-fold during HRT. However, the absolute risk remains low at approximately one occurrence in 5000 woman-years and appears greatest in the early years of HRT use. However, given that mortality from VTE is low, it seems unlikely that these new findings will substantially change the overall balance of benefits and risks associated with long-term HRT.

Hormone replacement therapy and cardiovascular risk: the cardiovascular physicians' viewpoint

Sufficient evidence has accumulated showing that hormone replacement therapy (HRT) does protect against cardiovascular disease in women, although data regarding the true magnitude of that protection remains incomplete. There is no evidence that HRT increases the risk of hypertension or thromboembolism, and beneficial effects have been found for plasma lipids, clotting factors and cardiovascular haemodynamics. However, the evidence is not convincing of any beneficial effect of HRT in preventing strokes, and concerns about the risk of cancer with HRT remain. Despite this, considerable uncertainty continues to exist amongst clinicians as to the balance of beneficial and harmful effects from administering HRT. Overall, HRT seems to do no harm and may be protective. A much greater awareness of the long-term consequences of the menopause and the potential benefits of HRT should be encouraged so that women (and their doctors) can make informed decisions about their requirements.

Epidemiological overview of oestrogen replacement and cardiovascular disease

In contrast to numerous epidemiological studies of prevention in men, there has been limited research into the prevention of cardiovascular disease in women. Nevertheless, sufficient data have accumulated showing that OeRT does protect against circulatory disease in women, although evidence regarding the true magnitude of that protection remains incomplete. The best estimates of the relationship between OeRT and CVD come from population-based prospective studies which are remarkably consistent: overall they indicate a 40% reduction in CVD with use of OeRT. However, because of the underlying better health of the postmenopausal women who use hormone replacement therapy, this result probably overestimates the benefit of OeRT by an unknown degree. Furthermore, details of OeRT formulation (especially the influence of regimens with an added progestin), dose, duration, and route of administration have not been adequately studied, and the evidence regarding the effect of OeRT on rates of stroke is equivocal and requires clarification. Oestrogen's cardioprotection appears to derive from favourable effects on serum lipoprotein profiles. There may also be a direct effect on the arterial system. Detrimental influences of OeRT on haemostatic function seem unlikely. Definitive information about the actual size of effects of commonly-used regimens of OeRT on cardiovascular disease and intermediate endpoints such as serum lipid concentrations can only be obtained through large-scale randomized controlled trials. Even if the reduction in CVD were modest, the mortality rates of CVD in our society are still so high that widespread use of oestrogen replacement therapy would result in substantial numbers of women's lives being saved.

Can we improve compliance with long-term HRT?

In order to increase awareness of strategies to prevent osteoporosis and heart disease we designed a clinic offering education and screening to all women aged 40-60 years on our practice list of 8600 patients, starting in January 1988. Screening and supervision of HRT users occurred at a weekly clinic run by the doctor and nurse. Audit in August 1991 showed that there were 260 present users of HRT (20%) of our population of 1322 women aged 40-60 years. Seventy-eight percent had taken HRT for over a year and 15% for more than 5 years. Ex-users totalled 117, of whom 52% had taken HRT for over a year and 14% for over 5 years. Examination of the clinic registers and responses to postal questionnaires showed that 681 (51.5%) of patients attended the health education clinic. Of the clinic attenders, 25% took HRT compared with 10.8% of non-attenders. Compliance with long-term therapy measured by audit of repeat prescriptions varied between 84% and 92% over a period of 5 years. Reasons for stopping treatment were anxiety over possible side-effects, especially breast cancer and dislike of bleeding.

The effect of oestrogen on the female cardiovascular system

OBJECTIVE

To review the present state of knowledge regarding the effect of oestrogen on the female cardiovascular system (e.g. atherosclerosis, myocardial infarction, hypertension and thrombosis).

DATA SOURCES

Over 100 articles (most published over the last 10 years) were reviewed. They included epidemiological, biochemical, physiological, animal and clinical studies which related to the effect oestrogens have on the cardiovascular system of postmenopausal women. These data contained a wide cross-section of results and outcomes and each study was summarised to provide the most relevant information. Where a particular study provided an opinion or result at variance with the majority opinion, that study has been discussed in greater detail.

STUDY SELECTION

All published papers which appeared to be relevant to an understanding of the clinical implications of oestrogen replacement therapy and its impact on the female cardiovascular system were included in this analysis. Some papers which appeared to repeat data and results previously published were not included.

DATA SYNTHESIS

The overwhelming eight of evidence from this literature review supports the concept that oestrogen reduces the risk of atherosclerosis and myocardial infarction. It also confirms that postmenopausal "natural" oestrogen is a vasodilating agent which will lead to a fall in blood pressure and an improvement in blood flow and the pulsatility index. Although oral oestrogen did appear to increase thrombogenic activity, there was no clinical evidence that "natural" oestrogen taken after the menopause increased the risk of venous thrombosis.

CONCLUSIONS

The consensus of the published data is that oestrogen conveys a highly protective effect on the cardiovascular system of postmenopausal women. There will be a reduction of up to 50% in myocardial infarction and stroke, a reduction in the incidence of hypertension and an improvement in blood flow. Some of the data suggest that even for women who have suffered from an infarct, their long-term survival is enhanced by oestrogen therapy. The medical myth that oestrogen has a deleterious effect on the cardiovascular system of women is finally laid to rest.